Rheem Water Heater 6 3 Flashes [Reasons + Solutions]

Many people complain that their Rheem water heater 6 3 flashes. It is a common problem in Rheem water heaters and the reasons behind this problem include flame sensor problems, damaged insulation, a leak in the water heater, and more.

In this article, we will discuss the common reasons behind this problem and their solutions.

The reasons and solutions of the Rheem water heater 6 3 error code problem discussed here will help you to solve the problem by yourself without calling professional help. So, let’s begin.

Rheem Water Heater 6 3 Flashes [Reasons + Solutions]

In this section, we will sort out the reasons behind your Rheem water heater 6 3 error codes and their solutions.

1. Flame Sensor Problem

If the flame sensor is dirty, your Rheem water heater will turn off after some seconds or minutes. Your Rheem water heater will also show 6 3 flashes.


To solve this problem, you need to clean the flame sensor of the Rheem water heater. You can do sanding and watch YouTube videos to clean the flame sensor.

2. Damaged Insulation

There is insulation in the back of the front cover of the pilot light assembly of your Rheem water heater.

The small strip of this insulation can get damaged, causing the Rheem water heater to show 6 3 flashes. This damaged insulation will also cause you to restart the water heater several times before it would stay on.


Firstly, you need to buy some pipe insulation for around 6 dollars. Now, you need to cut a strip around 12 inches long.

After that, you need to cut it width-wise in half. If it is not completely shrouding the oval holes with the bottom of the water heater, then set it in with the foil into the inside part.

Finally, you need to put the screws back in and put one nut on the top to solve this problem.

3. A Leak In The Water Heater

Sometimes, you can find some water in the bottom of the water heater because of a slow leak in your Rheem water heater.

If there is a such leak in your heater, it would cause the water heater to start and stop 3 times. It will also cause the Rheem water heater 6 flashes and then 3 flashes.


To solve this, you need to first fix the leak. Then, dried out the water. After drying out, the water heater will start working and it takes around two days to dry out completely.

If the water heater doesn’t dry out after 2 days then put a fan in front of it and it will dry up quickly. Hopefully, after a few more days, the water heater will completely dry out and start working.

4. Combustion Air Blockage

Combustion air blockage or insufficient combustion air will cause the pilot and main burner to douse before the water gets to the set point. It will cause your Rheem water heater to show 6 3 flashes and not work.


Firstly, ensure air inlet holes on the side of the water heater are neat and clean. You need to also ensure that the unit has an abundance of fresh air for combustion. This way you can solve this problem.

5. Pilot Tube Limitation

Pilot tube limitation or pinching will cause an insufficient amount of fuel to support the pilot flame and flame rectification of your Rheem water heater. It will cause your Rheem water heater to show the 6 3 error code and not work.


To solve this, you need to check the pilot tube for obstacles and pinched tubing. If any obstacle is found in the pilot tube, replace it.


How To Read Rheem Water Heater Model Numbers?

The data tag or label on your Rheem water heater’s external has your Rheem water heater model number. The model number is also found on the right side of the heater body or on the upper left side of the unit.

What Setting Should My Rheem Water Heater Be On?

Though you are permitted to set your Rheem water heater’s temperature anywhere between 32.2°C to 65.5°C, it is suggested not to set your heat very high. According to the Consumer Product Safety Commission, your hot water cylinder setting should be not more than 49°C. So, you can go with 49°C which is also the Rheem water heater’s standard factory setting

Where Is The Reset Button On A Rheem Furnace?
To find the reset button on a Rheem furnace, you need to remove the access panel from the furnace blower motor housing and look inside. You will see a little red or yellow button on the side of the blower motor which is the reset button on a Rheem furnace.

How To Reset FVS On Rheem Water Heater?

Firstly, you need to shut off the Rheem water heater’s gas valve switch. Then, you need to wait for a few seconds. After that, you need to reverse the gas valve switch to the “ON” position to reset the system. The Rheem water heater’s gas valve is situated near the bottom of the unit and attaches to your house’s natural gas line.

Why Won’t My Rheem Water Heater Light?

While a blocked gas line is one major reason why a Rheem water heater won’t light, there are some other reasons also. They are a defective thermocouple, failed gas valve, or something as little as a draft coming from a rupture in the wall or underneath the door.


Frequently there are some steps you can take to troubleshoot any problems, and the Rheem water heater 6 3 flashes problem is not different too. In this article, we have shown you those steps by discussing 5 reasons and solutions to this problem. 

We are hopeful that this article will help you to solve this problem easily and save you from a service call. Nevertheless, if this problem still hasn’t been solved, then let us know in the comment box. We will try to solve it as soon as possible.

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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